Role Of Maternal Sin3a In Reprogramming Gene Expression During Mouse Preimplantation Development

In mouse, the maternal-to-zygotic transition entails a dramatic reprogramming of gene expression during the course of zygotic genome activation, which is essential for continued development beyond the 2-cell stage. Superimposed on zygotic genome activation and reprogramming of gene expression is formation of a chromatin-mediated transcriptionally repressive state that promotes repression of genes at the 2-cell stage. Experimentally inducing global histone hyperacetylation relieves this repression and histone deacetylase 1 (HDAC1) is the major HDAC involved in the development of this transcriptionally repressive state. Because SIN3A is essential for mouse development and is part of a HDAC1/2-containing complex, I investigated the role of maternal SIN3A in the development of the global transcriptionally repressive state that develops during the course of genome activation and reprogramming. In addition, previous microarray data generated from our lab of oligo (dT) primed mouse oocyte and 1-cell embryo cDNA revealed an elevation in the relative abundance of the Sin3a transcript between the oocyte and 1-cell stages; the elevation in relative transcript abundance suggests that the Sin3a transcript undergoes translational recruitment during oocyte maturation because the elevation occurs during a period of transcriptional quiescence. Here I show that the Sin3a transcript is recruited for translation during oocyte maturation and following fertilization. I demonstrated that maternal SIN3A is essential for preimplantation development and the reprogramming of genes expression, because inhibiting the maturation-associated increase in SIN3A leads to an arrest in mouse embryonic development and unfaithful reprogramming of gene expression in 2-cell mouse embryos. The mid 1-cell embryo contains the maximum level of maternal SIN3A protein and the protein then rapidly decreases to essentially an undetectable level by the mid 2-cell stage; the rapid loss of maternal SIN3A is likely mediated by the proteasome because a proteasome inhibitor substantially inhibits the loss of maternal SIN3A. Due to the restricted presence of the maturation-associated increase in SIN3A, the function of maternal SIN3A is likely constrained to the 1-cell stage of mouse development. However, the increase in maternal SIN3A does not play a role in the minor ZGA, as depleting maternal SIN3A had no effect on global transcription in 1-cell embryos, but surprisingly results in histone hypoacetylation in 1-cell mouse embryos. Maintaining the presence of maternal SIN3A beyond the 1-cell stage had no effect on pre- and postimplantation development. Collectively, these findings indicate that the maturation-associated increase in SIN3A regulates the reprogramming of gene expression and the oocyte may utilize the translational recruitment of transcripts encoding chromatin-modifying-related factors during oocyte maturation as a post-transcriptional mechanism to faithfully execute the reprogramming of gene expression through the utilization of a maternally-derived transcription machinery

Nuevos registros de musgos del Bosque Chaqueño Seco en Santiago del Estero, Argentina.

Background and aims: The bryophyte flora of Argentina is currently under study, nevertheless, there are still extensive areas unexplored, such as Santiago del Estero with only three records of bryophytes to the entire region. The aim of this work was to contribute to the knowledge of the moss flora of Santiago del Estero province, through the collection of samples in Copo National Park and surroundings. M&M: The specimens were collected in the Copo National Park and surroundings, processed and studied according to traditional techniques for bryophytes. Microscopic characters were observed with stereoscopic and light microscopy. A list of the species found is presented, with comments on the differentiating characters, habitat and distribution. Results: The following moss taxa were found to be new records for the province: Aloina rigida; Dimerodontium balansae; Didymodon umbrosus; Fabronia ciliaris; Macrocoma tenuis subsp. sullivantii; Pseudocrossidium arenicola; P. linearifolium; Stereophyllum radiculosum; Syntrichia chisosa, Trichostomum brachydontium and Venturiella glaziovii. The range of distribution of Tricherpodium beccarii is extended to the northeast of the province. Conclusions: Eleven species and one subspecies, distributed in ten genera and five families, are newly reported for the province of Santiago del Estero. The range of distribution of one species is extended to the northeast of the province. These first studies highlight the unexplored floristic richness of the region and its vulnerability due to the accelerated advance of the agricultural-livestock borderIntroducción y objetivos: La flora briofítica en Argentina se encuentra actualmente en estudio, sin embargo, todavía quedan extensas áreas sin explorar, como lo es la provincia de Santiago del Estero, con solo tres registros de briófitos en toda la región. El objetivo de este trabajo es contribuir al conocimiento de la flora de musgos de la provincia de Santiago del Estero a través de colecciones en el Parque Nacional Copo y sus alrededores. M&M: Las muestras fueron coleccionadas, procesadas y examinadas de acuerdo a las técnicas clásicas para briófitos. Los caracteres microscópicos fueron observados con microscopio óptico y estereoscópico. Se presenta un listado de las especies hasta el momento encontradas en la provincia, con comentarios sobre el hábitat y la distribución. Resultados: Los siguientes taxa de musgos se registran por primera vez para la provincia: Aloina rigida; Dimerodontium balansae; Didymodon umbrosus; Fabronia ciliaris; Macrocoma tenuis subsp. sullivantii; Pseudocrossidium arenicola; P. linearifolium; Stereophyllum radiculosum; Syntrichia chisosa, Trichostomum brachydontium y Venturiella glaziovii. El rango de distribución de Tricherpodium beccarii se amplía hacia el noreste de la provincia. Conclusiones: Once especies y una subespecie, distribuidas en diez géneros y cinco familias se registran por primera vez para Santiago del Estero. El rango de distribución de una especie se extiende al noreste de la provincia. Estos primeros estudios ponen de manifiesto la riqueza florística inexplorada de la región, y la vulnerabilidad de la misma debido al acelerado avance de la frontera agrícola ganaderaFil: Jimenez, Maria Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Suarez, Guillermo Martin. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Cabral, Richard A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; Argentin

Calymperaceae, una nueva familia para la flora briológica de Uruguay

Introducción y objetivos: El objetivo de este trabajo es contribuir al conocimiento de la flora de briófitos en Uruguay, por medio del estudio de colecciones realizadas en el Parque Nacional Fortaleza Santa Teresa. M&M: Las muestras se coleccionaron, procesaron y analizaron morfológicamente mediante técnicas convencionales para briófitas. Los caracteres microscópicos se observaron e ilustraron con microscopía óptica (LM) y microscopía electrónica de barrido (MEB). Resultados: La familia Calymperaceae Kindb. se registra por primera vez en el país, representada por Syrrhopodon gaudichaudii Mont. Esta especie se caracteriza por las hojas crispadas cuando secas, con margen liso a dentado en el ápice. Conclusiones: Se presenta una descripción detallada e ilustraciones en MO y MEB de S. gaudichaudii.Background and aims: The aim of this work was to increase the knowledge of the bryoflora of Uruguay based on the analysis of samples collected in Fortaleza Santa Teresa National Park. M&M: Specimens were collected, processed and analyzed morphologically using conventional techniques for bryophytes. Microscopic characters were observed and illustrated with light microscopy (LM) and scanning electron microscopy (SEM). Results: Calymperaceae Kindb. are recorded for the first time to the country, represented by Syrrhopodon gaudichaudii Mont. This species is characterized by leaves strongly crispate when dry, and margins smooth to dentate at the apex. Conclusions: A detailed description, illustrations with SEM and LM of S. gaudichaudii is here presented.Fil: Cabral, Richard A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Jimenez, Maria Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Suárez, Guillermo M.. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto Miguel Lillo; Argentin

Morphological Analysis of Activity-Reduced Adult-Born Neurons in the Mouse Olfactory Bulb

Adult-born neurons (ABNs) are added to the olfactory bulb (OB) throughout life in rodents. While many factors have been identified as regulating the survival and integration of ABNs into existing circuitry, the understanding of how these factors affect ABN morphology and connectivity is limited. Here we compare how cell intrinsic [small interfering RNA (siRNA) knock-down of voltage gated sodium channels NaV1.1–1.3] and circuit level (naris occlusion) reductions in activity affect ABN morphology during integration into the OB. We found that both manipulations reduce the number of dendritic spines (and thus likely the number of reciprocal synaptic connections) formed with the surrounding circuitry and inhibited dendritic ramification of ABNs. Further, we identified regions of ABN apical dendrites where the largest and most significant decreases occur following siRNA knock-down or naris occlusion. In siRNA knock-down cells, reduction of spines is observed in proximal regions of the apical dendrite. This suggests that distal regions of the dendrite may remain active independent of NaV1.1–1.3 channel expression, perhaps facilitated by activation of T-type calcium channels and NMDA receptors. By contrast, circuit level reduction of activity by naris occlusion resulted in a global depression of spine number. Together, these results indicate that ABNs retain the ability to develop their typical overall morphological features regardless of experienced activity, and activity modulates the number and location of formed connections

BDNF val66met polymorphism is associated with modified experience-dependent plasticity in human motor cortex.

Motor training can induce profound physiological plasticity within primary motor cortex, including changes in corticospinal output and motor map topography. Using transcranial magnetic stimulation, we show that training-dependent increases in the amplitude of motor-evoked potentials and motor map reorganization are reduced in healthy subjects with a val66met polymorphism in the brain-derived neurotrophic factor gene (BDNF), as compared to subjects without the polymorphism. The results suggest that BDNF is involved in mediating experience-dependent plasticity of human motor cortex

Climate change and the kidney

The worldwide increase in temperature has resulted in a marked increase in heat waves (heat extremes) that carries a markedly increased risk for morbidity and mortality. The kidney has a unique role not only in protecting the host from heat and dehydration but also is an important site of heat-associated disease. Here we review the potential impact of global warming and heat extremes on kidney diseases. High temperatures can result in increased core temperatures, dehydration, and blood hyperosmolality. Heatstroke (both clinical and subclinical whole-body hyperthermia) may have a major role in causing both acute kidney disease, leading to increased risk of acute kidney injury from rhabdomyolysis, or heat-induced inflammatory injury to the kidney. Recurrent heat and dehydration can result in chronic kidney disease (CKD) in animals and theoretically plays a role in epidemics of CKD developing in hot regions of the world where workers are exposed to extreme heat. Heat stress and dehydration also has a role in kidney stone formation, and poor hydration habits may increase the risk for recurrent urinary tract infections. The resultant social and economic consequences include disability and loss of productivity and employment. Given the rise in world temperatures, there is a major need to better understand how heat stress can induce kidney disease, how best to provide adequate hydration, and ways to reduce the negative effects of chronic heat exposure.Published versio

Apportionment of primary and secondary organic aerosols in Southern California during the 2005 Study of Organic Aerosols in Riverside (SOAR-1)

Ambient sampling was conducted in Riverside, California during the 2005 Study of Organic Aerosols in Riverside to characterize the composition and sources of organic aerosol using a variety of state-of-the-art instrumentation and source apportionment techniques. The secondary organic aerosol (SOA) mass is estimated by elemental carbon and carbon monoxide tracer methods, water soluble organic carbon content, chemical mass balance of organic molecular markers, and positive matrix factorization of high-resolution aerosol mass spectrometer data. Estimates obtained from each of these methods indicate that the organic fraction in ambient aerosol is overwhelmingly secondary in nature during a period of several weeks with moderate ozone concentrations and that SOA is the single largest component of PM1 aerosol in Riverside. Average SOA/OA contributions of 70−90% were observed during midday periods, whereas minimum SOA contributions of ~45% were observed during peak morning traffic periods. These results are contrary to previous estimates of SOA throughout the Los Angeles Basin which reported that, other than during severe photochemical smog episodes, SOA was lower than primary OA. Possible reasons for these differences are discussed

Update on obesity and obesity paradox in heart failure

Obesity has reached epidemic proportions in most of the Westernized world. Overweightness and obesity adversely impact cardiac structure and function, including on both the right and, especially, left sides of the heart, with adverse affects on systolic and, especially, diastolic ventricular function. Therefore, it is not surprising that obesity markedly increases the prevalence of heart failure (HF). Nevertheless, many studies have documented an obesity paradox in large cohorts with HF, where overweight and obese have a better prognosis, at least in the short-term, compared with lean HF patients. Although weight loss clearly improves cardiac structure and function and reduces symptoms in HF, there are no large studies on the impact of weight loss on clinical events in HF, preventing definitive guidelines on optimal body composition in patients with HF

High-resolution NMR studies of structure and dynamics of human ERp27 indicate extensive interdomain flexibility

ERp27 (endoplasmic reticulum protein 27.7 kDa) is a homologue of PDI (protein disulfide-isomerase) localized to the endoplasmic reticulum. ERp27 is predicted to consist of two thioredoxinfold domains homologous with the non-catalytic b and b domains of PDI. The structure in solution of the N-terminal blike domain of ERp27 was solved using high-resolution NMR data. The structure confirms that it has the thioredoxin fold and that ERp27 is a member of the PDI family. 15N-NMR relaxation data were obtained and ModelFree analysis highlighted limited exchange contributions and slow internal motions, and indicated that the domain has an average order parameter S 2 of 0.79. Comparison of the single-domain structure determined in the present study with the equivalent domain within fulllength ERp27, determined independently by X-ray diffraction, indicated very close agreement. The domain interface inferred from NMR data in solution was much more extensive than that observed in the X-ray structure, suggesting that the domains flex independently and that crystallization selects one specific interdomain orientation. This led us to apply a new rapid method to simulate the flexibility of the full-length protein, establishing that the domains show considerable freedom to flex (tilt and twist) about the interdomain linker, consistent with the NMR data

The Lyth Bound and the End of Inflation

We derive an extended version of the well-known Lyth Bound on the total variation of the inflaton field, incorporating higher order corrections in slow roll. We connect the field variation $\Delta\phi$ to both the spectral index of scalar perturbations and the amplitude of tensor modes. We then investigate the implications of this bound for ``small field'' potentials, where the field rolls off a local maximum of the potential. The total field variation during inflation is {\em generically} of order $m_{\rm Pl}$, even for potentials with a suppressed tensor/scalar ratio. Much of the total field excursion arises in the last e-fold of inflation and in single field models this problem can only be avoided via fine-tuning or the imposition of a symmetry. Finally, we discuss the implications of this result for inflationary model building in string theory and supergravity.Comment: 10 pages, RevTeX, 2 figures (V3: version accepted for publication by JCAP